As more and more companies rely on computer networks as an integral part of doing business, it is becoming increasingly desirable to maintain accurate topology maps for such networks. And, with computer networks continuing to expand both in complexity and scope, using manual means to maintain accurate topology maps is becoming a very difficult to impossible endeavor.
Thus, systems and methods have been developed to attempt to automatically obtain information about networks in order to create topology maps. These systems and methods include U.S. Pat. No. 5,727,157 to Orr et al., entitled "Apparatus and Method for Determining a Computer Network Topology"; U.S. Pat. No. 5,450,408 to Phaal et al., entitled "Method of Ascertaining Topology Features of a Network"; U.S. Pat. No. 5,297,138 to Black, entitled "Determining Physical Topology Across Repeaters and Bridges in a Computer Network"; and PCT International Publication No. WO 97/18659 to Dawes et al., entitled "Method of Determining the Topology of a Network of Objects."
Each of these systems and methods have limitations that prevent them from fulfilling the industry's needs for timely and accurate network topology information. For example, the method disclosed by Dawes et al., which measures traffic information on a given network, suffers from an inability to obtain accurate topology features in a timely manner. Indeed, independent tests performed by Network Computing Magazine on Loran Technologies implementation of the method disclosed by Dawes et al. showed that this method required one month before accurate results were obtained. During the three month testing period, the accuracy rose to approximately 90%. ("Network Computing", "Network Management Solutions Lack Clear Leader", Vol. 9, No. 15, Aug. 15, 1998, pp. 62, 64). The Phaal et al. patent, on the other hand, requires implementing probes throughout the global network which can require a significant amount of administrative effort.
Also, while the Black and the Orr patents utilize source address table information contained within network devices in an effort to resolve topology features of computer networks, the disclosed methods are brute force approaches that do not take account of critical device and connectivity information when attempting to determine network interconnections.
In sum, there remains a need for a system and method for determining accurate topology features of a network. The invention described herein employs an organizational approach performed on logical groupings to avoid ambiguity by design. In particular, the preferred embodiment utilizes a combination of logical groupings called circuits and link domains to avoid inaccuracies. (These concepts and other concepts relevant to the present invention are discussed below.) Moreover, the present invention preferably utilizes various filters on device source address table information and router ARP table information to ensure that the topology information is accurate. The end result is that connections can be calculated using any standard sorting function--resulting in a timely and accurate determination of device connections from which a network topology map can be displayed.